T.J. Turnage and Jared Maples National Weather Service Grand Rapids, Michigan
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Transcript of T.J. Turnage and Jared Maples National Weather Service Grand Rapids, Michigan
Two Cases of QLCS Tornadic Wind Estimation and Implications for Impact Based Warnings
T.J. Turnage and Jared Maples National Weather Service
Grand Rapids, Michigan
Outline
QLCS tornado climatology
Impact Assessment
Warning decisions
QLCS Tornado Climatology
% tornado days due to lines1998 - 2000
Trapp et al. 2005
● larger proportion of F1 tornadoes from QLCSs than cells● smaller proportion of F0 tornadoes - likely underreported● more F3–F4 tornadoes from cells
Trapp et al. 2005
QLCS Tornado Climatology
Significant Severe Climatology
Thompson et al. 2013
Courtesy of SPC
Outline
QLCS tornado climatology
Impact Assessment
Warning decisions
Goals● Provide valuable information● Help improve public response● Better addressing of societal
needs
Impact Assessment
What is the IBW experiment?● Began in 2012● Distinguish low and high
impact events● Indicate levels of risk
Impact Based Warnings
http://www.crh.noaa.gov/crh/?n=2013_ibw_info
Phenomena
Impacts
Impact Assessment
*FLYING DEBRIS DANGEROUS TOTHOSE WITHOUT SHELTER
*MOBILE HOMES DAMAGED OR DESTROYED
*DAMAGE TO ROOFS ...WINDOWS… VEHICLES
*TREE DAMAGE LIKELY
*FLYING DEBRIS DANGEROUS TO THOSEWITHOUT SHELTER
*MOBILE HOMES HEAVILY DAMAGED
*CONSIDERABLE DAMAGE TO ROOFS…WINDOWS...VEHICLES
*EXTENSIVE TREE DAMAGE ANDPOWER OUTAGES
Significant SVR
Default TOR
Impact Assessment
REMAIN ALERT FOR A POSSIBLE TORNADO! TORNADOES CAN DEVELOP QUICKLY FROM SEVERE THUNDERSTORMS. IF YOU SPOT A TORNADO GO AT ONCE INTO THE BASEMENT OR SMALL CENTRAL ROOM IN A STURDY STRUCTURE.
INTENSE SQUALL LINES CAN SOMETIMES PRODUCE BRIEF TORNADOES AND WIDESPREAD SIGNIFICANT WIND DAMAGE. ALTHOUGH A TORNADO IS NOT IMMEDIATELY LIKELY...IT IS BEST TO MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A BUILDING. THIS STORM MAY CAUSE SERIOUS INJURY AND SIGNIFICANT PROPERTY DAMAGE
TORNADO...POSSIBLE
Impact Assessment
Outline
QLCS tornado climatology
Impact Assessment
Warning decisions
Decision Factors
Near StormEnvironment(NSE)
StormInterrogation
Ground Truth
Warning Decisions
Near Storm Environment (NSE)SPC Tornado Environment Browser
Case 1
06/22/2010 ~04Z
Near Storm Environment (NSE)
MLCAPE MLCIN
Nontor EF0 EF2+
Thompson et al. 2013
Nontor EF0 EF2+
06/22/2010 04Z
0-6 km BWDEffective BWD
Nontor EF0 EF2+
0-1 km BWD
Nontor EF0 EF2+
Near Storm Environment (NSE)06/22/2010 04Z
Thompson et al. 2013
STPEffective STP
Nontor EF0 EF2+
0-1 km SRHEffective SRH
Nontor EF0 EF2+
Near Storm Environment (NSE)06/22/2010 04Z
Thompson et al. 2013
Atkins and St. Laurent MWR 2009
Storm Interrogation Principles
Descending TVS
Non-Descending TVS
Trapp and Weisman 2003
Trapp et al. 1999
Storm Interrogation Principles
Where did the “tornado” occur?
06/22/2010 04ZReflectivity NROTStorm Interrogation
N
06/22/2010 04ZStorm Interrogation
Gravity wave interaction?
TroughCrest
06/22/2010 04ZStorm Interrogation
Case 2
11/17/2013 ~19Z
Near Storm Environment (NSE)
MLCAPE MLCIN
Nontor EF0 EF2+
Thompson et al. 2013
Nontor EF0 EF2+
11/17/2013 19Z
0-6 km BWDEffective BWD
Nontor EF0 EF2+
0-1 km BWD
Nontor EF0 EF2+
Near Storm Environment (NSE)
Thompson et al. 2013
11/17/2013 19Z
STPEffective STP
Nontor EF0 EF2+
0-1 km SRHEffective SRH
Nontor EF0 EF2+
Near Storm Environment (NSE)
Thompson et al. 2013
11/17/2013 19Z
Reflectivity NROT11/17/2013 19ZStorm Interrogation
N
11/17/2013 19ZStorm Interrogation
11/17/2013 19ZStorm Interrogation
SummaryQLCS Tornadoes
• Climatologically common
• Climatology strongly favors ≤ EF1 wind
• Damage often looks like “straight line” wind
• Similar impacts to SVR t-storms
Summary (cont)
• Shear / SRH best discriminate significant
tornado environments
• MLCAPE / MLCIN / STP less helpful
Warning Decision - NSE
Summary (cont)
• QLCS mesovortices:
• Usually north of bow apex
• Strongest wind south of circulation
• May or may not descend
• Intensity often regulated by gravity waves
• Radar presentation can be deceptive
Warning Decision – Storm Interrogation
Thank you!
Atkins, Nolan T., Michael St. Laurent, 2009: Bow Echo Mesovortices. Part I: Processes That Influence Their Damaging Potential. Mon.
Wea. Rev.,137, 1497–1513.
Thompson, R.; Smith, B.; Dean, A.; Marsh, P.. Spatial Distributions of Tornadic Near-Storm Environments by Convective Mode. E-Journal
of Severe Storms Meteorology, North America, 8 1 09 2013.
Trapp, R. J., E. D. Mitchell, G. A. Tipton, D. W. Effertz, A. I. Watson, D. L. Andra, M. A. Magsig, 1999: Descending and Nondescending
Tornadic Vortex Signatures Detected by WSR-88Ds. Wea. Forecasting, 14, 625–639.
Trapp, Robert J., Sarah A. Tessendorf, Elaine Savageau Godfrey, Harold E. Brooks, 2005: Tornadoes from Squall Lines and Bow Echoes. Part
I: Climatological Distribution. Wea. Forecasting, 20, 23–34.
Trapp, Robert J., Morris L. Weisman, 2003: Low-Level Mesovortices within Squall Lines and Bow Echoes. Part II: Their Genesis and
Implications.Mon. Wea. Rev., 131, 2804–2823.
Impact Based Warnings:
References
http://www.crh.noaa.gov/crh/?n=2013_ibw_info